#include<stdio.h>

int main(int argc, char *argv[])
{
	int arr[] = {1,2,3,4,5,6,7,8,9,10};
	int left = 0;
	int right = sizeof(arr)/sizeof(int) - 1;
	int mid;
	int num;
	scanf("%d", &num);
	while(left <= right){
		mid = left +(right - left) / 2;
		if(arr[mid] == num){
			break;
		}else if(arr[mid] > num){
			right = mid -1;
		}else if(arr[mid] < num){
			left = mid + 1;
		}		
	}
	if(left <= right){
		printf("%d", mid);
	}else{
		printf("no");
	}
	return 0;
}
